What is the water quality grade for Missisquoi Bay Lake?

Missisquoi Bay Lake in Franklin County, Vermont received a water quality grade of C (Fair). Water clarity: 5.6 ft visibility. Phosphorus: 34.5 µg/L. Chlorophyll-a (algae): 12.1 µg/L.

Is Missisquoi Bay Lake safe to swim in?

Generally safe for swimming, moderate water quality. Missisquoi Bay Lake has an overall water quality grade of C. Algae concentration (chlorophyll-a) is 12.1 µg/L. Always check local health department advisories before swimming.

Franklin County, Vermont

Missisquoi Bay Lake

Grade CFair · 5.6 ft clarity

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Eutrophic

Missisquoi Bay Lake is a productive, nutrient-rich eutrophic lake in Franklin County, Vermont. Water quality is graded C based on 3 sampling years through 2025. Compared to the 8 other monitored lakes in Franklin County, Missisquoi Bay Lake ranks #8 for water quality.

Source: EPA Water Quality Portal sampling records, Vermont DNR, last sampled 2025-08-08. Grade methodology: LakeGrade methodology.

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Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

Murky, only visible to about 5.6 ft. Phosphorus level: 34.5 µg/L. Chlorophyll-a: 12.1 µg/L. Trophic State Index: 54.

Metric	Value	Grade
Water Clarity (Secchi Depth)	5.6 ft	D
Phosphorus	34.5 µg/L	C
Chlorophyll-a (Algae)	12.1 µg/L	C
Trophic State Index (TSI)	54	Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Missisquoi Bay Lake

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